/*
 * Copyright (c) 2007, 2021, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.sun.org.apache.xml.internal.utils;

import java.util.Locale;

/**
 * The default implementation of the XMLString interface,
 * which is just a simple wrapper of a String object.
 */
public class XMLStringDefault implements XMLString {

    private String m_str;

    /**
     * Create a XMLStringDefault object from a String
     */
    public XMLStringDefault(String str) {
        m_str = str;
    }

    /**
     * Directly call the
     * characters method on the passed ContentHandler for the
     * string-value. Multiple calls to the
     * ContentHandler's characters methods may well occur for a single call to
     * this method.
     *
     * @param ch A non-null reference to a ContentHandler.
     * @throws org.xml.sax.SAXException
     */
    public void dispatchCharactersEvents(org.xml.sax.ContentHandler ch)
            throws org.xml.sax.SAXException {
    }

    /**
     * Directly call the
     * comment method on the passed LexicalHandler for the
     * string-value.
     *
     * @param lh A non-null reference to a LexicalHandler.
     * @throws org.xml.sax.SAXException
     */
    public void dispatchAsComment(org.xml.sax.ext.LexicalHandler lh)
            throws org.xml.sax.SAXException {
    }

    /**
     * Conditionally trim all leading and trailing whitespace in the specified String.
     * All strings of white space are
     * replaced by a single space character (#x20), except spaces after punctuation which
     * receive double spaces if doublePunctuationSpaces is true.
     * This function may be useful to a formatter, but to get first class
     * results, the formatter should probably do it's own white space handling
     * based on the semantics of the formatting object.
     *
     * @param trimHead                Trim leading whitespace?
     * @param trimTail                Trim trailing whitespace?
     * @param doublePunctuationSpaces Use double spaces for punctuation?
     * @return The trimmed string.
     */
    public XMLString fixWhiteSpace(boolean trimHead,
                                   boolean trimTail,
                                   boolean doublePunctuationSpaces) {
        return new XMLStringDefault(m_str.trim());
    }

    /**
     * Returns the length of this string.
     *
     * @return the length of the sequence of characters represented by this
     * object.
     */
    public int length() {
        return m_str.length();
    }

    /**
     * Returns the character at the specified index. An index ranges
     * from <code>0</code> to <code>length() - 1</code>. The first character
     * of the sequence is at index <code>0</code>, the next at index
     * <code>1</code>, and so on, as for array indexing.
     *
     * @param index the index of the character.
     * @return the character at the specified index of this string.
     * The first character is at index <code>0</code>.
     * @throws IndexOutOfBoundsException if the <code>index</code>
     *                                   argument is negative or not less than the length of this
     *                                   string.
     */
    public char charAt(int index) {
        return m_str.charAt(index);
    }

    /**
     * Copies characters from this string into the destination character
     * array.
     *
     * @param srcBegin index of the first character in the string
     *                 to copy.
     * @param srcEnd   index after the last character in the string
     *                 to copy.
     * @param dst      the destination array.
     * @param dstBegin the start offset in the destination array.
     * @throws IndexOutOfBoundsException If any of the following
     *                                   is true:
     *                                   <ul><li><code>srcBegin</code> is negative.
     *                                   <li><code>srcBegin</code> is greater than <code>srcEnd</code>
     *                                   <li><code>srcEnd</code> is greater than the length of this
     *                                       string
     *                                   <li><code>dstBegin</code> is negative
     *                                   <li><code>dstBegin+(srcEnd-srcBegin)</code> is larger than
     *                                       <code>dst.length</code></ul>
     * @throws NullPointerException      if <code>dst</code> is <code>null</code>
     */
    public void getChars(int srcBegin, int srcEnd, char dst[],
                         int dstBegin) {
        int destIndex = dstBegin;
        for (int i = srcBegin; i < srcEnd; i++) {
            dst[destIndex++] = m_str.charAt(i);
        }
    }

    /**
     * Compares this string to the specified <code>String</code>.
     * The result is <code>true</code> if and only if the argument is not
     * <code>null</code> and is a <code>String</code> object that represents
     * the same sequence of characters as this object.
     *
     * @param obj2 the object to compare this <code>String</code> against.
     * @return <code>true</code> if the <code>String</code>s are equal;
     * <code>false</code> otherwise.
     * @see java.lang.String#compareTo(java.lang.String)
     * @see java.lang.String#equalsIgnoreCase(java.lang.String)
     */
    public boolean equals(String obj2) {
        return m_str.equals(obj2);
    }

    /**
     * Compares this string to the specified object.
     * The result is <code>true</code> if and only if the argument is not
     * <code>null</code> and is a <code>String</code> object that represents
     * the same sequence of characters as this object.
     *
     * @param anObject the object to compare this <code>String</code>
     *                 against.
     * @return <code>true</code> if the <code>String </code>are equal;
     * <code>false</code> otherwise.
     * @see java.lang.String#compareTo(java.lang.String)
     * @see java.lang.String#equalsIgnoreCase(java.lang.String)
     */
    public boolean equals(XMLString anObject) {
        return m_str.equals(anObject.toString());
    }


    /**
     * Compares this string to the specified object.
     * The result is <code>true</code> if and only if the argument is not
     * <code>null</code> and is a <code>String</code> object that represents
     * the same sequence of characters as this object.
     *
     * @param anObject the object to compare this <code>String</code>
     *                 against.
     * @return <code>true</code> if the <code>String </code>are equal;
     * <code>false</code> otherwise.
     * @see java.lang.String#compareTo(java.lang.String)
     * @see java.lang.String#equalsIgnoreCase(java.lang.String)
     */
    public boolean equals(Object anObject) {
        return m_str.equals(anObject);
    }

    /**
     * Compares this <code>String</code> to another <code>String</code>,
     * ignoring case considerations.  Two strings are considered equal
     * ignoring case if they are of the same length, and corresponding
     * characters in the two strings are equal ignoring case.
     *
     * @param anotherString the <code>String</code> to compare this
     *                      <code>String</code> against.
     * @return <code>true</code> if the argument is not <code>null</code>
     * and the <code>String</code>s are equal,
     * ignoring case; <code>false</code> otherwise.
     * @see #equals(Object)
     * @see java.lang.Character#toLowerCase(char)
     * @see java.lang.Character#toUpperCase(char)
     */
    public boolean equalsIgnoreCase(String anotherString) {
        return m_str.equalsIgnoreCase(anotherString);
    }

    /**
     * Compares two strings lexicographically.
     *
     * @param anotherString the <code>String</code> to be compared.
     * @return the value <code>0</code> if the argument string is equal to
     * this string; a value less than <code>0</code> if this string
     * is lexicographically less than the string argument; and a
     * value greater than <code>0</code> if this string is
     * lexicographically greater than the string argument.
     * @throws java.lang.NullPointerException if <code>anotherString</code>
     *                                        is <code>null</code>.
     */
    public int compareTo(XMLString anotherString) {
        return m_str.compareTo(anotherString.toString());
    }

    /**
     * Compares two strings lexicographically, ignoring case considerations.
     * This method returns an integer whose sign is that of
     * <code>this.toUpperCase().toLowerCase().compareTo(
     * str.toUpperCase().toLowerCase())</code>.
     * <p>
     * Note that this method does <em>not</em> take locale into account,
     * and will result in an unsatisfactory ordering for certain locales.
     * The java.text package provides <em>collators</em> to allow
     * locale-sensitive ordering.
     *
     * @param str the <code>String</code> to be compared.
     * @return a negative integer, zero, or a positive integer as the
     * the specified String is greater than, equal to, or less
     * than this String, ignoring case considerations.
     * @see java.text.Collator#compare(String, String)
     * @since 1.2
     */
    public int compareToIgnoreCase(XMLString str) {
        return m_str.compareToIgnoreCase(str.toString());
    }

    /**
     * Tests if this string starts with the specified prefix beginning
     * a specified index.
     *
     * @param prefix  the prefix.
     * @param toffset where to begin looking in the string.
     * @return <code>true</code> if the character sequence represented by the
     * argument is a prefix of the substring of this object starting
     * at index <code>toffset</code>; <code>false</code> otherwise.
     * The result is <code>false</code> if <code>toffset</code> is
     * negative or greater than the length of this
     * <code>String</code> object; otherwise the result is the same
     * as the result of the expression
     * <pre>
     *          this.subString(toffset).startsWith(prefix)
     *          </pre>
     * @throws java.lang.NullPointerException if <code>prefix</code> is
     *                                        <code>null</code>.
     */
    public boolean startsWith(String prefix, int toffset) {
        return m_str.startsWith(prefix, toffset);
    }

    /**
     * Tests if this string starts with the specified prefix beginning
     * a specified index.
     *
     * @param prefix  the prefix.
     * @param toffset where to begin looking in the string.
     * @return <code>true</code> if the character sequence represented by the
     * argument is a prefix of the substring of this object starting
     * at index <code>toffset</code>; <code>false</code> otherwise.
     * The result is <code>false</code> if <code>toffset</code> is
     * negative or greater than the length of this
     * <code>String</code> object; otherwise the result is the same
     * as the result of the expression
     * <pre>
     *          this.subString(toffset).startsWith(prefix)
     *          </pre>
     * @throws java.lang.NullPointerException if <code>prefix</code> is
     *                                        <code>null</code>.
     */
    public boolean startsWith(XMLString prefix, int toffset) {
        return m_str.startsWith(prefix.toString(), toffset);
    }

    /**
     * Tests if this string starts with the specified prefix.
     *
     * @param prefix the prefix.
     * @return <code>true</code> if the character sequence represented by the
     * argument is a prefix of the character sequence represented by
     * this string; <code>false</code> otherwise.
     * Note also that <code>true</code> will be returned if the
     * argument is an empty string or is equal to this
     * <code>String</code> object as determined by the
     * {@link #equals(Object)} method.
     * @throws java.lang.NullPointerException if <code>prefix</code> is
     *                                        <code>null</code>.
     * @since JDK1. 0
     */
    public boolean startsWith(String prefix) {
        return m_str.startsWith(prefix);
    }

    /**
     * Tests if this string starts with the specified prefix.
     *
     * @param prefix the prefix.
     * @return <code>true</code> if the character sequence represented by the
     * argument is a prefix of the character sequence represented by
     * this string; <code>false</code> otherwise.
     * Note also that <code>true</code> will be returned if the
     * argument is an empty string or is equal to this
     * <code>String</code> object as determined by the
     * {@link #equals(Object)} method.
     * @throws java.lang.NullPointerException if <code>prefix</code> is
     *                                        <code>null</code>.
     * @since JDK1. 0
     */
    public boolean startsWith(XMLString prefix) {
        return m_str.startsWith(prefix.toString());
    }

    /**
     * Tests if this string ends with the specified suffix.
     *
     * @param suffix the suffix.
     * @return <code>true</code> if the character sequence represented by the
     * argument is a suffix of the character sequence represented by
     * this object; <code>false</code> otherwise. Note that the
     * result will be <code>true</code> if the argument is the
     * empty string or is equal to this <code>String</code> object
     * as determined by the {@link #equals(Object)} method.
     * @throws java.lang.NullPointerException if <code>suffix</code> is
     *                                        <code>null</code>.
     */
    public boolean endsWith(String suffix) {
        return m_str.endsWith(suffix);
    }

    /**
     * Returns a hashcode for this string. The hashcode for a
     * <code>String</code> object is computed as
     * <blockquote><pre>
     * s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
     * </pre></blockquote>
     * using <code>int</code> arithmetic, where <code>s[i]</code> is the
     * <i>i</i>th character of the string, <code>n</code> is the length of
     * the string, and <code>^</code> indicates exponentiation.
     * (The hash value of the empty string is zero.)
     *
     * @return a hash code value for this object.
     */
    public int hashCode() {
        return m_str.hashCode();
    }

    /**
     * Returns the index within this string of the first occurrence of the
     * specified character. If a character with value <code>ch</code> occurs
     * in the character sequence represented by this <code>String</code>
     * object, then the index of the first such occurrence is returned --
     * that is, the smallest value <i>k</i> such that:
     * <blockquote><pre>
     * this.charAt(<i>k</i>) == ch
     * </pre></blockquote>
     * is <code>true</code>. If no such character occurs in this string,
     * then <code>-1</code> is returned.
     *
     * @param ch a character.
     * @return the index of the first occurrence of the character in the
     * character sequence represented by this object, or
     * <code>-1</code> if the character does not occur.
     */
    public int indexOf(int ch) {
        return m_str.indexOf(ch);
    }

    /**
     * Returns the index within this string of the first occurrence of the
     * specified character, starting the search at the specified index.
     * <p>
     * If a character with value <code>ch</code> occurs in the character
     * sequence represented by this <code>String</code> object at an index
     * no smaller than <code>fromIndex</code>, then the index of the first
     * such occurrence is returned--that is, the smallest value <i>k</i>
     * such that:
     * <blockquote><pre>
     * (this.charAt(<i>k</i>) == ch) && (<i>k</i> >= fromIndex)
     * </pre></blockquote>
     * is true. If no such character occurs in this string at or after
     * position <code>fromIndex</code>, then <code>-1</code> is returned.
     * <p>
     * There is no restriction on the value of <code>fromIndex</code>. If it
     * is negative, it has the same effect as if it were zero: this entire
     * string may be searched. If it is greater than the length of this
     * string, it has the same effect as if it were equal to the length of
     * this string: <code>-1</code> is returned.
     *
     * @param ch        a character.
     * @param fromIndex the index to start the search from.
     * @return the index of the first occurrence of the character in the
     * character sequence represented by this object that is greater
     * than or equal to <code>fromIndex</code>, or <code>-1</code>
     * if the character does not occur.
     */
    public int indexOf(int ch, int fromIndex) {
        return m_str.indexOf(ch, fromIndex);
    }

    /**
     * Returns the index within this string of the last occurrence of the
     * specified character. That is, the index returned is the largest
     * value <i>k</i> such that:
     * <blockquote><pre>
     * this.charAt(<i>k</i>) == ch
     * </pre></blockquote>
     * is true.
     * The String is searched backwards starting at the last character.
     *
     * @param ch a character.
     * @return the index of the last occurrence of the character in the
     * character sequence represented by this object, or
     * <code>-1</code> if the character does not occur.
     */
    public int lastIndexOf(int ch) {
        return m_str.lastIndexOf(ch);
    }

    /**
     * Returns the index within this string of the last occurrence of the
     * specified character, searching backward starting at the specified
     * index. That is, the index returned is the largest value <i>k</i>
     * such that:
     * <blockquote><pre>
     * this.charAt(k) == ch) && (k <= fromIndex)
     * </pre></blockquote>
     * is true.
     *
     * @param ch        a character.
     * @param fromIndex the index to start the search from. There is no
     *                  restriction on the value of <code>fromIndex</code>. If it is
     *                  greater than or equal to the length of this string, it has
     *                  the same effect as if it were equal to one less than the
     *                  length of this string: this entire string may be searched.
     *                  If it is negative, it has the same effect as if it were -1:
     *                  -1 is returned.
     * @return the index of the last occurrence of the character in the
     * character sequence represented by this object that is less
     * than or equal to <code>fromIndex</code>, or <code>-1</code>
     * if the character does not occur before that point.
     */
    public int lastIndexOf(int ch, int fromIndex) {
        return m_str.lastIndexOf(ch, fromIndex);
    }

    /**
     * Returns the index within this string of the first occurrence of the
     * specified substring. The integer returned is the smallest value
     * <i>k</i> such that:
     * <blockquote><pre>
     * this.startsWith(str, <i>k</i>)
     * </pre></blockquote>
     * is <code>true</code>.
     *
     * @param str any string.
     * @return if the string argument occurs as a substring within this
     * object, then the index of the first character of the first
     * such substring is returned; if it does not occur as a
     * substring, <code>-1</code> is returned.
     * @throws java.lang.NullPointerException if <code>str</code> is
     *                                        <code>null</code>.
     */
    public int indexOf(String str) {
        return m_str.indexOf(str);
    }

    /**
     * Returns the index within this string of the first occurrence of the
     * specified substring. The integer returned is the smallest value
     * <i>k</i> such that:
     * <blockquote><pre>
     * this.startsWith(str, <i>k</i>)
     * </pre></blockquote>
     * is <code>true</code>.
     *
     * @param str any string.
     * @return if the string argument occurs as a substring within this
     * object, then the index of the first character of the first
     * such substring is returned; if it does not occur as a
     * substring, <code>-1</code> is returned.
     * @throws java.lang.NullPointerException if <code>str</code> is
     *                                        <code>null</code>.
     */
    public int indexOf(XMLString str) {
        return m_str.indexOf(str.toString());
    }

    /**
     * Returns the index within this string of the first occurrence of the
     * specified substring, starting at the specified index. The integer
     * returned is the smallest value <i>k</i> such that:
     * <blockquote><pre>
     * this.startsWith(str, <i>k</i>) && (<i>k</i> >= fromIndex)
     * </pre></blockquote>
     * is <code>true</code>.
     * <p>
     * There is no restriction on the value of <code>fromIndex</code>. If
     * it is negative, it has the same effect as if it were zero: this entire
     * string may be searched. If it is greater than the length of this
     * string, it has the same effect as if it were equal to the length of
     * this string: <code>-1</code> is returned.
     *
     * @param str       the substring to search for.
     * @param fromIndex the index to start the search from.
     * @return If the string argument occurs as a substring within this
     * object at a starting index no smaller than
     * <code>fromIndex</code>, then the index of the first character
     * of the first such substring is returned. If it does not occur
     * as a substring starting at <code>fromIndex</code> or beyond,
     * <code>-1</code> is returned.
     * @throws java.lang.NullPointerException if <code>str</code> is
     *                                        <code>null</code>
     */
    public int indexOf(String str, int fromIndex) {
        return m_str.indexOf(str, fromIndex);
    }

    /**
     * Returns the index within this string of the rightmost occurrence
     * of the specified substring.  The rightmost empty string "" is
     * considered to occur at the index value <code>this.length()</code>.
     * The returned index is the largest value <i>k</i> such that
     * <blockquote><pre>
     * this.startsWith(str, k)
     * </pre></blockquote>
     * is true.
     *
     * @param str the substring to search for.
     * @return if the string argument occurs one or more times as a substring
     * within this object, then the index of the first character of
     * the last such substring is returned. If it does not occur as
     * a substring, <code>-1</code> is returned.
     * @throws java.lang.NullPointerException if <code>str</code> is
     *                                        <code>null</code>.
     */
    public int lastIndexOf(String str) {
        return m_str.lastIndexOf(str);
    }

    /**
     * Returns the index within this string of the last occurrence of
     * the specified substring.
     *
     * @param str       the substring to search for.
     * @param fromIndex the index to start the search from. There is no
     *                  restriction on the value of fromIndex. If it is greater than
     *                  the length of this string, it has the same effect as if it
     *                  were equal to the length of this string: this entire string
     *                  may be searched. If it is negative, it has the same effect
     *                  as if it were -1: -1 is returned.
     * @return If the string argument occurs one or more times as a substring
     * within this object at a starting index no greater than
     * <code>fromIndex</code>, then the index of the first character of
     * the last such substring is returned. If it does not occur as a
     * substring starting at <code>fromIndex</code> or earlier,
     * <code>-1</code> is returned.
     * @throws java.lang.NullPointerException if <code>str</code> is
     *                                        <code>null</code>.
     */
    public int lastIndexOf(String str, int fromIndex) {
        return m_str.lastIndexOf(str, fromIndex);
    }

    /**
     * Returns a new string that is a substring of this string. The
     * substring begins with the character at the specified index and
     * extends to the end of this string. <p>
     * Examples:
     * <blockquote><pre>
     * "unhappy".substring(2) returns "happy"
     * "Harbison".substring(3) returns "bison"
     * "emptiness".substring(9) returns "" (an empty string)
     * </pre></blockquote>
     *
     * @param beginIndex the beginning index, inclusive.
     * @return the specified substring.
     * @throws IndexOutOfBoundsException if
     *                                   <code>beginIndex</code> is negative or larger than the
     *                                   length of this <code>String</code> object.
     */
    public XMLString substring(int beginIndex) {
        return new XMLStringDefault(m_str.substring(beginIndex));
    }

    /**
     * Returns a new string that is a substring of this string. The
     * substring begins at the specified <code>beginIndex</code> and
     * extends to the character at index <code>endIndex - 1</code>.
     * Thus the length of the substring is <code>endIndex-beginIndex</code>.
     *
     * @param beginIndex the beginning index, inclusive.
     * @param endIndex   the ending index, exclusive.
     * @return the specified substring.
     * @throws IndexOutOfBoundsException if the
     *                                   <code>beginIndex</code> is negative, or
     *                                   <code>endIndex</code> is larger than the length of
     *                                   this <code>String</code> object, or
     *                                   <code>beginIndex</code> is larger than
     *                                   <code>endIndex</code>.
     */
    public XMLString substring(int beginIndex, int endIndex) {
        return new XMLStringDefault(m_str.substring(beginIndex, endIndex));
    }

    /**
     * Concatenates the specified string to the end of this string.
     *
     * @param str the <code>String</code> that is concatenated to the end
     *            of this <code>String</code>.
     * @return a string that represents the concatenation of this object's
     * characters followed by the string argument's characters.
     * @throws java.lang.NullPointerException if <code>str</code> is
     *                                        <code>null</code>.
     */
    public XMLString concat(String str) {
        return new XMLStringDefault(m_str.concat(str));
    }

    /**
     * Converts all of the characters in this <code>String</code> to lower
     * case using the rules of the given <code>Locale</code>.
     *
     * @param locale use the case transformation rules for this locale
     * @return the String, converted to lowercase.
     * @see java.lang.Character#toLowerCase(char)
     * @see java.lang.String#toUpperCase(Locale)
     */
    public XMLString toLowerCase(Locale locale) {
        return new XMLStringDefault(m_str.toLowerCase(locale));
    }

    /**
     * Converts all of the characters in this <code>String</code> to lower
     * case using the rules of the default locale, which is returned
     * by <code>Locale.getDefault</code>.
     * <p>
     *
     * @return the string, converted to lowercase.
     * @see java.lang.Character#toLowerCase(char)
     * @see java.lang.String#toLowerCase(Locale)
     */
    public XMLString toLowerCase() {
        return new XMLStringDefault(m_str.toLowerCase());
    }

    /**
     * Converts all of the characters in this <code>String</code> to upper
     * case using the rules of the given locale.
     *
     * @param locale use the case transformation rules for this locale
     * @return the String, converted to uppercase.
     * @see java.lang.Character#toUpperCase(char)
     * @see java.lang.String#toLowerCase(Locale)
     */
    public XMLString toUpperCase(Locale locale) {
        return new XMLStringDefault(m_str.toUpperCase(locale));
    }

    /**
     * Converts all of the characters in this <code>String</code> to upper
     * case using the rules of the default locale, which is returned
     * by <code>Locale.getDefault</code>.
     *
     * <p>
     * If no character in this string has a different uppercase version,
     * based on calling the <code>toUpperCase</code> method defined by
     * <code>Character</code>, then the original string is returned.
     * <p>
     * Otherwise, this method creates a new <code>String</code> object
     * representing a character sequence identical in length to the
     * character sequence represented by this <code>String</code> object and
     * with every character equal to the result of applying the method
     * <code>Character.toUpperCase</code> to the corresponding character of
     * this <code>String</code> object. <p>
     * Examples:
     * <blockquote><pre>
     * "Fahrvergn&uuml;gen".toUpperCase() returns "FAHRVERGN&Uuml;GEN"
     * "Visit Ljubinje!".toUpperCase() returns "VISIT LJUBINJE!"
     * </pre></blockquote>
     *
     * @return the string, converted to uppercase.
     * @see java.lang.Character#toUpperCase(char)
     * @see java.lang.String#toUpperCase(Locale)
     */
    public XMLString toUpperCase() {
        return new XMLStringDefault(m_str.toUpperCase());
    }

    /**
     * Removes white space from both ends of this string.
     * <p>
     * If this <code>String</code> object represents an empty character
     * sequence, or the first and last characters of character sequence
     * represented by this <code>String</code> object both have codes
     * greater than <code>'&#92;u0020'</code> (the space character), then a
     * reference to this <code>String</code> object is returned.
     * <p>
     * Otherwise, if there is no character with a code greater than
     * <code>'&#92;u0020'</code> in the string, then a new
     * <code>String</code> object representing an empty string is created
     * and returned.
     * <p>
     * Otherwise, let <i>k</i> be the index of the first character in the
     * string whose code is greater than <code>'&#92;u0020'</code>, and let
     * <i>m</i> be the index of the last character in the string whose code
     * is greater than <code>'&#92;u0020'</code>. A new <code>String</code>
     * object is created, representing the substring of this string that
     * begins with the character at index <i>k</i> and ends with the
     * character at index <i>m</i>-that is, the result of
     * <code>this.substring(<i>k</i>,&nbsp;<i>m</i>+1)</code>.
     * <p>
     * This method may be used to trim
     * {@link Character#isSpace(char) whitespace} from the beginning and end
     * of a string; in fact, it trims all ASCII control characters as well.
     *
     * @return this string, with white space removed from the front and end.
     */
    public XMLString trim() {
        return new XMLStringDefault(m_str.trim());
    }

    /**
     * This object (which is already a string!) is itself returned.
     *
     * @return the string itself.
     */
    public String toString() {
        return m_str;
    }

    /**
     * Tell if this object contains a java String object.
     *
     * @return true if this XMLString can return a string without creating one.
     */
    public boolean hasString() {
        return true;
    }

    /**
     * Convert a string to a double -- Allowed input is in fixed
     * notation ddd.fff.
     *
     * @return A double value representation of the string, or return Double.NaN
     * if the string can not be converted.
     */
    public double toDouble() {
        try {
            return Double.valueOf(m_str).doubleValue();
        } catch (NumberFormatException nfe) {
            return Double.NaN;
        }
    }
}
